Fix ConcurrentModificationException in TouchInteractionService

Bug: 381018493
Test: Manual, i.e. verified that unregistering listener during set iteration works
Flag: EXEMPT bugfix
Change-Id: Ia4600797ce579b80621b32977fcd9712d4fc26bb
diff --git a/quickstep/src/com/android/quickstep/TouchInteractionService.java b/quickstep/src/com/android/quickstep/TouchInteractionService.java
index 8edb16f..1739480 100644
--- a/quickstep/src/com/android/quickstep/TouchInteractionService.java
+++ b/quickstep/src/com/android/quickstep/TouchInteractionService.java
@@ -524,7 +524,8 @@
         }
 
         protected void onOverviewTargetChange() {
-            for (Runnable listener : mOnOverviewTargetChangeListeners) {
+            Set<Runnable> listeners = new HashSet<>(mOnOverviewTargetChangeListeners);
+            for (Runnable listener : listeners) {
                 listener.run();
             }
         }